1. Field of the Invention
This invention pertains to hinge arrangements, joints and systems for pivotally coupling two or more objects together, and more particularly to an articulating hinge assembly which provides for pivotally coupling objects together with precise, incremental ratcheting pivotal motion upon application of a small amount of force to the hinged objects.
2. Description of the Background Art
Numerous coupling systems are known which provide for pivotally coupling various objects. Many coupling systems provide for articulating pivotal movement so that coupled objects may be positioned relative to each other in incremental adjustments. Articulating coupling systems which allow incremental positional adjustment sometimes use an arrangement wherein teeth or like structures in one coupling member engage or intermesh with corresponding teeth in another coupling member. Application of force to one or both of the coupling members or the objects coupled thereto causes the teeth to disengage and reengage in a new position.
A problem with articulating coupling systems which provide such incremental adjustment occurs when such systems are used for joining together thin, resilient, highly flexible objects or objects made of materials having weak or poor mechanical properties. The amount of force necessary to cause pivotal motion in standard articulating coupling systems can be greater than the force required to deform, bend or even break a resilient or weak object or objects associated with the coupling system. This problem is illustrated by the disposable face shield devices which are increasingly used in the medical and dental professions. Generally, it is desirable for face shields to be pivotally mounted on a head-worn visor or like apparatus. The wearer of the face shield positionally adjusts the face shield by applying force to the face shield to cause pivotal motion of the face shield relative to the head-worn visor, thereby allowing the wearer to move the face shield into desired positions. Some face shields, however, are made of transparent, flexible polymeric sheet material of thin construction in order to keep material costs low. Such sheet materials are easily bent or deformed, and the force required for pivotal adjustment of a disposable face shield while using standard pivotal coupling systems generally exceeds the force necessary to bend the material of the face shield. Thus, the wearer of such a face shield cannot readily adjust the position of the face shield by pushing on the face shield, but must remove the head worn face shield and manipulate the hinge assembly directly to change the pivotal position of the face shield. The wearers of face shields, however, are frequently engaged in complex clinical procedures wherein the wearer cannot use both hands to make positional adjustments of the face shield or to remove the face shield to make such adjustments.
Accordingly, there is a need for an articulating hinge system which provides precise incremental adjustment to coupled objects upon application of a relatively small amount of force to the pivotally coupled objects, and which is suitable for use with easily bendable and easily deformable objects. The present invention satisfies these needs, as well as others, and generally overcomes the deficiencies found in the background art.